Table of adjustable height



April 8, 1958 c. D. GlBsoN 2,829,863

TABLE 0F ADJUSTABLE HEIGHT Filed July 25, 1952 4 sheets-'sheet 1 M8 //0 /ag /2 JNI/ENTOR.

TTOR NE Y prl 8, 1958 c. D. GIBSON' TABLE oF ADJUSTABLE HEIGHT 4 Sheets-Sheet 2 Filed July 23, 1952 f1 TTORNE Y April 8, 1958 c; D. GIBSON 2,829,863

` TABLE OF ADJUSTABLE HEIGHT Filed July 25, 1952 y 4 Sheets-Sheet 3 25 @e 98 ,/7 //2 7 94 2&4 40 46 #14 2/ '42 72 76 341 IN VEN TOR. HQ/SWAN@ G/o/V TTORNEY April 8, 1958 c. D. GIBSON 2,829,863

TABLE oF ADJUSTABLE HEIGHT Filed July 2s. 1952 4 sheets-sheet 4 INVENTOR. C//fe/v/,q/v 0. G/fa/v I WORNEY United States Patent() TABLE F ADJUSTABLE HEIGHT Christian D. Gibson, Greene, N. Y., assignor to The Raymond Corporation, Greene, N. Y., a corporation of New York Application July 23, 1952, Serial No. 300,387

6 Claims. (Cl. 254-S) This invention relates Ato material handling devices and particularly to a table of adjustable height upon which materials or tools to be used in a manufacturing operation may be supported in proximity to the operation and quickly brought to the most convenient height for transfer to the operation. Tables of the type to which the invention particularly relates have been found to have great utility in supporting a stack, pile or bundle vof metal sheets in proximity to a machine which is to operate upon the sheets in succession, the provision for quickly and easily adjusting the height of the table top or sheetsupporting surface of the table making it possible to bring the top sheet of the pile to such a level that the operator can slide the top sheet to the press, shear, brake or other machine without any manual lifting.

It is important that tables of the aforementioned type, which are usually provided with wheels and/or casters to permit them to be loaded in the storage area and then readily moved to the machine which is to operate upon the metal sheets -or other material piled thereon, be of such rugged construction that they can support and lift comparatively heavy loads, that they be stable in all positions of adjustment, that theyv be capable of a considerable range Aof adjustment, so that a bundle or stack of substantial height may be taken to the machine oneach trip, and that the number of levels of adjustment within the adjustmentrange be infinite. It is also important that there be such four-point support of the load-carrying tabletop at all times and suchoverall stability of the table as a whole that there will be no sagging with olicenter loads.

With the foregoing considerations in view the invention aims to provideV a` table of adjustable height for the purposes hereinabove set forth which has therein the above Arecited, desirable features of construction and in which novel and improved means for effecting the adjustment of the height of the material-supporting top of the table make possiblethe production of a table of adjustable 'height having the Vruggedness, the capacity for handling comparatively heavy loads and for quickly and easily adjusting them to the desired height, the strong four-point support in all positions of adjustment and the stability which are so essential to a commercially practicable-device of this character.

An important feature of the invention is the use of .a single-throw lever` of the lazy vtongs type, more commonly calleda-lever of the scissors type, between the table base and-the table top to effect the lifting and lowering movements of the top and the mounting of .scissors-operating hydraulic jacks upon the scissors levers themselves in such manner that they directly reinforce the lifting and supporting functions of the scissors arms and can move with them into a compact collapsed position, but a position, nevertheless, in which they can exert effective scissors opening or table top lifting force upon `the scissors lever arms.

`Another important feature of the invention is the pivotalconnection of the hydraulic jacks to the scissors 1 Patented Apr. 8, 1958 ice arms by means of pivots carried by brackets which rigidly oset said pivots from the planes defined by the connections between the scissors arms and the table 4base and top, thereby permitting jacks of greater length and therefore of higher effective lift to operate between the scissors arms.

Other important features of the invention are the novel pivotal interconnection of the scissors arms by which relatively wide` bearings are obtained and the location of the hydraulic jacks to provide for direct four-point lifting action and for reinforcement yof the four-point supporting action -of the scissors arms. Still other objects. important features and advantages of the invention. to which reference has not specifically been made hereinabove will lbe apparent when the following specification and claims are considered in connection with the accompanying drawings, in which:

Figure 1 is a perspective view of a table of adjustable height embodying `the present invention;

Figure 2 is a detail rear elevation of the left hand part of the table;

Figure 3 is a section on the line 3-3 of either Figure 2 or Figure 6 looking in the direction of the arrows in either ligure, this view also showing in dotted lines the position of the parts when the -top is elevated;

Figure 4 is a section on the line 4-4 of Figure 6 `looking in the direction of the arrow;

Figure 5 is a section onthe line 5-5 of Figure 6 looking in the direction of the arrow;

Figure `6 is a plan view of the table with the top removed, this view showing, among other things, the arrangement of the conduits which supply hydraulic liquid to the jacks that elevate the table top; and

Figure 7 is a central Avertical section through a table having a modified arrangement of the connections between the scissors arms and the table base and top supporting frames, the jacks being omitted.

The table of adjustable height herein `shown comprises a base frame consisting of channel side mem-bers 4, a cross channel 6 welded to the side channels and an angle plate 8 welded to the front ends of the side channels 4 and reinforced and stiifened by vertical plates 10 welded both to the angle plate 8 and to the side channels 4. The rear end of the base 'frame is supported on wheels 12 having antifriction bearings 14 on a cross shaft 16 extending through the side channels 4 and through reinforcing plates 18 and secured by nuts 20. At its front end `the base frame 2 is supported upon casters '22, A reinforced opening 24 in the horizontal part of the angle plate 8 may receive a hook or other means for drawing the table over the floor into material-feeding relation to the machine which is to operate upon `the material carriedY thereby.

The top-supporting frame of the table comprises side channels 28 and front and rear end channels 30 and 32 welded to the side ychannels to form an integral rectangular frame on which the material-supporting top plate 34 is carried, this plate being preferably welded to its supporting frame.

BetweenV the two frames above described is located the scissors lever which effects the raising and lowering of the table top 34 with its load of metal sheets or other material to be fed to the press, shear, brake or other machine which is to operate upon the material. The illustrated lever of the scissors type, or single throw lever of the lazy tongs type, comprises outer scissors arms 36 rigidly cross connected by tubular members 38 and 40, Welded or otherwise fixedly secured at or near their ends to the arms 36, and inner scissors arms 42 rigidly cross connected by means of tubular members 44 and 46 likewise welded or otherwise fixedly secured at or near their ends to the arms 42, the scissors arms thus rigidly cross connected constituting the two parts of the scissors lever assembly, these outer and inner scissors arms being pivotally interconnected at points substantially intermediate between theirends. Y ,l

The Ypivotal interconnection between the outerand inner scissors arms is shown' in detail at theright hand side of Figure 4 and in section in Figure 3. The inner vscissors arms 42 have, in addition to the cross connecting tubular members 44 and 46, a further cross connecting tubular member 48, of even larger diameter, welded at its ends to the arms 42 and surrounding a concentric inner tubular member 50 which extends through openings in the inner scissors arms 42 a Short distance'to form a hub-like extension and is'weldedvat 52 to the outer sides of the arms 42.

Short sections 54 oftubing of the same diameter as the tube 50 extend through openings in the outer scissors arms 36 to form bearing hubs and are welded to said arms upon each side thereof. The bearing hubsof considerable lateral extent thus provided have, between the said hubs and the pivot shaft 56, oilite or other suitable permanently lubricated anti-friction bearings 58jand 60. The pivot shaft 56 extends through the hubs54 a sufficient distance at its two ends to receive cotter pins 62 bearing against washers 64. p

The scissors lever assembly thus described is connected to the table base frame and table top supporting frame as as follows: The tubular cross connection 44 between the inner scissors arms 42 which is welded to said scissors arms, as shown at 65., surrounds the shaft 16 and is of sutiiciently larger inner diameter than the shaft 16 so that it does not touch the shaftrwhen the anti-friction bearing 66 is driven into the countersunk opening 68l in the end of the tubular member 44, this countersunk opening also extending through the scissors arm 42.V It will be noted that the outer end of the tubular member 44 is turned down to form a reduced hub-like extension 70 in which the bearing 68 is received and that this hub-like extenthrough the scissors arm 42 and bears against and helps position the anti-friction bearing assembly 14 for a supporting wheel 12.

At their other ends the inner scissors arms 42 are provided with rollers 72 which travel in guideways 74 in channel members 76 secured to plates 78 which, in turn, are secured at their ends and upper edges to the top supporting frame yand to the underside of the top 34 itself. These rollers 72 are carried upon studs 80 extending through the scissors arms 42 and secured in position by nuts 82.

The outer scissors arms 36 at their lower ends are provided with rollers 84 which travel in guideways 86 in channels 88 welded to the inner faces of the side channel bars 4 of theV base frame. These rollers 84, like the rollers 72 hereinabove described, are carried on studs 90 Vsecured in position in the scissors arms 36 by nuts 92.

At their upper ends the outer scissors arms 36 have pivotal connections to the top supporting frame, as follows: A third cross tubular member 94, which is welded to the scissors arms 36, like the cross tubular member 44, extends through the scissors arms to form a hub extension 95, which is countersunk on its interior to receive an antifriction or permanently lubricated bearing 96 upon a cross pivot shaft 98 extending through the side channel memlbers 28 of the top-supporting frame and through a reinforcing plate 100 a sufiicient distance to receive a cotter pin 102. There is thus formed a fixed pivotal connection at one end of the table between the top supporting frame and the outer scissors arms 36 and a fixed pivotal connection at the same end of the table between the inner scissors arms 42 and the base frame. At the other end of the ta-ble the outer scissors arms 36 have a sliding pivotal connection with the base frame and the inner scissors arms 42 have a sliding pivotal connection with the top frame..

To effect the opening and closing movements of the scissors assembly hereinabove described and thereby the lifting and lowering movements of the table top 34 and of any load carried thereon, hydraulic rams or jacks are arranged to operate between the outer scissors arms and the inner scissors arms on both sides of the pivotal connection between these arms, these rams or jacks being preferably of uniform capacity and being pivotally connected at their respective ends to the outer and inner scissors arms and being arranged to partake of the movements thereof. As herein shown, the cylinder part 106 of each ram or jack has a tongue extension 108 bored to receive a pivot pin 110 that is supported in brackets, as more fully hereinafter described. The piston part 112 of each ram or jack is likewise bored to receive a pivot pin 114 that is also received in brackets, as more fully hereinafter described. There are preferably four of these rams or jacks so located as to insure uniform four-point lifting and four-point reinforcement of the supporting function of the scissors lever.

As shown in Figure 5, the cylinders 106 of the rams or jacks at the forward or caster Vend of the table have their pivot pins 110 mounted in brackets 116, depending from and rigidlysecured to the cross tubular member 38 which extends between and at its ends is welded to the outer scissors arms 36. This offsetsvthe pivotal connection of the cylinder 106 from the cross tubular member 38 and from the p lane lof the pivotal connections between the outer scissors arms and the base and top frames and thus permits the ram or jackto move fromv the position shown in full lines in Figure 3 to the position shown in dotted lines in said figure as the lower ends of the outer scissors arms slide along the guideway in the base frame. It will be seen that there is a slight lifting as well as straightening of the rams or jacks at the forward end of the table during this lifting movement of the table top.

Cylinders 106 of the rams or jacks at the rear end of the table have their pivot pins 110 received in bracket arms 118 depending from and rigidly secured to the cross connecting tubular member 44 which surrounds the cross shaft 16 on which the wheels 12 are mounted. The tubular member 44 being rigidly attached to the scissors arms 42, the bracket arms 118 turn with the turning of the inner scissors arms 42 about the shaft 16 and thus carry the rams from the position shown in full lines in Figure 3 to the position shown in dotted lines in this figure, this movement both raising the rams or jacks slightly and causing them assume a more nearlyupright position. Y

Pistons 112 of the rams or jacks at the forward end of the top elevating mechanism have their pivot pins 114 received in bracket arms 113 and 115, the bracket arms 113 being mounted on and'rigidly welded tothe cross connecting tubular member 46 and the bracket arms 115 being welded to the inner sides of the scissors arms 42 and the cross connecting tube 46 being welded at its ends to the bracket arms or plates 115, as shown in Figures 5 and 6. As shown in Figure 3, the pivot pin receiving parts of the brackets 115 extend above the upper edges of the scissors arms 42. y

The pistons 112 of the rams or jacks at the rear end of the top elevating mechanism have their pivot pins 114 received in bracket arms 117 rigidly ysecured to the crossconnecting tubular member 40 which extends between and is welded at itsends to the outer scissors arms 36. The brackets 117 thus partake of the swinging movements of the arms 36 during the top lifting 'and lowering operations, as shown in Figure 3.

In Figurey 6 the connections to the hydraulic rams or jacks, by means of which they are supplied Ywith hydraulic -liquid under pressure,`ar'e shown. It`will be seen that a Ypipe coupling 120, attached to cross channel 6, has nexible connections 124 to the rear rams or jacks and that it isV provided with aremovable screw plug 126 so that it may be connected to a foot pump, power pump or other means for supplying hydraulic liquid under pressure. A tube 128 extends from the coupling 120 to a second coupling 130 attached to a cross plate 122 welded to the under side of the side channel member 4 of the base frame. From this coupling 130 llexible tubes 132 extend to the cylinders 106 of the forward rams or jacks. The flexible tubes 124 and 132 provide for the movement of the cylinders 106 with the scissors arms.

From the foregoing description it will be seen that the raising of the material-supporting table top 34 from the position shown in full lines in Figure 3 to the position shown in dotted lines therein is effected by introducing hydraulic liquid under pressure, as, for example, by means of a foot pump, into the coupling 120 through the opening shown as closed by the plug 126 in Figure 6, and that this causes the projection of the pistons 112 from the cylinders 106 with a resultant four-point application of pressure to the scissors lever to open it into the position shown in dotted lines in Figure 3. During this movement those ends of the scissors arms, which are provided with the sliding pivotal connections to the base and top through the rollers 72 and 84 travelling in the guides 74 and 86, move toward the left in Figures l and 3, the cylinders 106 and pistons 112 at this end of the scissors assembly also travelling with the ends of the scissors arms by reason of their support upon the cross connections 38 and 46, respectively.` This results in the forward rams or jacks assuming a more nearly vertical position. The jacks at the other end of the scissors assembly also assume a more nearly vertical position by reason of their being lifted and moved slightly forward by the brackets 118 as the scissors arms 42 rock about their bearings on the shaft 16 thus turning the cross tube 44, rigidly cross-connected to the outer scissors arms, also about the shaft 16. It will thus be seen that the location of the rams or jacks in the positions shown insures the most effective application of their scissors opening power to the scissors lever assembly and that the provision of four of these rams or jacks, spaced as shown, reinforces the four-point support of the table top and serves to insure stable support of the material carried thereby, even when in off center position on the top. The arrangement of the jacks as shown also insures compactness in the collapsed position of the elevating mechanism.

Figure 7 shows a slight modification of the connections between the scissors lever and the table top-supporting frame and table base. In this modified structure the two sliding pivots are carried by the same scissors arm and the two'xed pivots are connected to the other scissors arm. This modification has the slight disadvantage that there is a small longitudinal movement of the table top during its lifting and lowering movements.

What is claimed as new is:

1. A table of adjustable height for the purposes set forth having, in combination, a base frame and a top supporting frame, two pairs of rigidly cross-connected scissors arms located between said frames, the arms of one pair being respectively pivotally interconnected with the arms of the other pair at points substantially intermediate between the ends of said arms, tl e scissors assembly thus formed having at its top iixed pivotal connections at one end with the top supporting frame and sliding pivotal connections at its other end with said top supporting frame and said assembly having at its bottorn xed pivotal connections at one end to said base frame and sliding pivotal connections at its other end to said base frame, cross connections between the scissors arms of each pair being respectively located upon opposite sides of the scissors pivot and between said scissors pivot and the ends of said arms, and hydraulically interconnected scissors-operating hydraulic rams also located upon opposite sides of said scissors pivot and acting between and having pivotal connections to the correspondingly situated cross connections.

2. A table of adjustable height according to claim 1 in which the pivotal interconnection between the respective arms of the two pairs of scissors arms comprises a shaft extending across the scissors assembly upon which each scissors arm has a hub bearing, each hub bearing being a torque tube concentric with the pivotal interconnection between the pairs of arms and extending between and rigidly connected at its ends to the scissors arms of said inner pair 4. A table of adjustable height according to claim 1 in which two torque tubes concentric with each other and with the pivotal interconnection of the scissors assembly extend between and are rigidly connected to the scissors arms of the inner pair and in which a cross shaft extends across the scissors assembly upon which the inner tube has its bearings.

5. A table of adjustable height according to claim 1 in which brackets xed to rigid cross connections support the end pivots of the rams in offset relation to said cross connections.

6. A table of adjustable height according to claim l in which two hydraulic rams acting between the cross connections on each side of the pivotal interconnection between the scissors arms are respectively so laterally spaced as to provide substantial four-point support of the top frame.

References Cited in the le of this patent UNITED STATES PATENTS 

